Method and apparatus for coating material



Jul 10, 1923.

P. SCHWERIN METHOD AND APPARATUS FOR COATING MATERIAL l7 1919 2Sheets-Sheet 1 Filed Oct.

July 10, 1923. 1,461,228

P. SCHWERlN METHOD AND APPARATUS FOR COATING MATERIQL Filed 001;. 17,1919 2 Sheets-Sheet 2 Fig. 2

lnvenfor Pau/ Schwer/h Patented July 10, 1923.

UNITED STATES 1,461,228 PATENT OFFICE.

PAUL SOHWERIN, OF NEW YORK, N. Y., ASSIGNOB TO WESTERN ELECTRICCOEIPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

METHOD AND APPARATUS FOR COATING MATERIAL.

Application filed October 17, 1919. Serial No. 331,334.

a To all wham'it may concern:

Be it known that 1, PAUL ScHwnRIN, a citizen of the United States,residing at New York, in the county of Bronx, State of New York, haveinvented certain new and useful Improvements in Methods and Apparatusfor Coating Material, of which the following is a full, clear, concise,and exact description.

This invention relates to a method and apparatus for coating materialand has particular reference to the coating of filamentary material suchas is used for electrodes in vacuum tubes.

An object of the invention is to increase therate of production offilamentary coated material and to decrease its.cost of production.

The invention provides an endless conveyer on which is mounted atsuitabl intervals a quantity of material grippers. Bjetween one gripperand an adjacent one a definite length of material is gripped and movedalong over a bath of coating liquid. This liquid is applied to thematerial by contact with a plurality of devices to which the liquid issuitably applied. During the time the liquid is being applied, a currentis passed through the material to glow it and causes baking of thecoating on the material. The plurality of coating devices are spacedapart so that between each coating device and the adjacent one, thecurrent will glow the wire previous to the application of more coatingliquid by the next device. The material is then fed along until it isadjacent another conveyer frame which may be called the baking frame. Atthis instant electrical circuit connections are made which off. Thesecondconveyer then continues to move in a definite manner and for adefinite distance until a circuit-breaking mechanism is brought intoplay to stop the second conveyer in a definite position, whereupon it isin position to receive another length of material to be baked. Theconveyer baking frame ls-capable of receiving a large number of lengthsof materials sothat each of the lower end of the baking frame and,

in particular, the manner of operation of the material gripping means onthe drying frame; Fig. 3 represents a section taken through the mainconveyer showing, in detail, the structure of the material gripper, andFig. 4 is a detailed view of the relation between the coating mechanismand the mechanism which drives the same.

The invention as shown in the drawings comprises an endless conveyerbelt 1, which passes at each end over rollers 3 and a. Power to drivethe conveyer belt 1 is re ceived from a suitable motor 5 attached to theroller 3. Adjacent the edges of the belt 1 are tracks 6 and 7 formed ofangle iron beams along which a plurality of pairs of pulley frames 8 areadapted to move. These pulley frames comprise (see Fig. 3) an upper bar9 and a lower bar 10, suitably fastened together with the belt 1 betweenthem, by means of screws 11. The upper bar 9 is adapted to receive ashaft 12 having at its ends the pulleys 13 and 14. These pulleys travelalongthe upper edges of the tracks 6 and 7. The lower bar 10 has adownwardly extended portion 15 which is connected to a gripper or clip16. One side of this gripper or clip 16 is provided with an arm 17 whichhas on its upper end a roller 18.

The tracks 6 and 7 are cut away at a point 19 and adjacent this cut-awayportion is a vertical frame 20 which has a lower surface correspondingin outline to the cutaway portion 19 of the tracks. The distance betweenthe lower surface of its frame 20 and the nearest cut-away portion ofthe tracks 6 and 7 is equal to the diameter of 7 reaches this cut-awayportion, it will move downward into the cut-away portion and be so toopen the material grippers 16. Imme diately after this happens thepulley frames 8 descend into thev cut-away portion 19 of the tracks 6and 7, but the grippers 16 are still maintained open by reason of thefact that the rollers 18 continue to contact with a forward portion ofthe cam 22. In this lowermost portion the grippers are open and in aposition to grip the filamentary material 23 which is fed through aguide loop 24 from a reel 25. The cam 22 is attached to the track 7 bymeans of a bracket 26.

As the pulley frames 8 continue to advance the forward edge of thecut-away portions 19 are encountered which cause the pulley frames toascend. Just prior to the time the pulley frames begin to ascend. theroller 18 moves off the front edge of the cam surface 22 therebypermitting the grippers 16 to close and grip the filamentary material23. The material is thereupon continuously and slowly moved forward,another pulley frame, a desired length of time thereafter, being causedto grip and lift the filamentary material a definite distance behind theone previously mentioned. In Fig. 1 it will be noted that sections ofthe rails 6 and 7 are insulated as at 6 and 7' so that potential is notapplied to the grippers until after the material is gripped and thusprevents fusing the material due to imperfect contact.

As the material is fed forward in a somewhat slack loop form, it passesover and contacts with the upper surfaces of a plurality of groovedrollers 27 which are suitably journallcd in a tank 28 containing coatingliquid and under which suitable heating means .(not shown) is placed.These rollers are driven by gears 29 and 30 from a motor 31. The tankandthe motor are mounted on a platform 32. The rollers 27 are so positionedthat their lower surfaces di in the coating liquid and their rotationcauses this liquid to'be rubbed on to the filamentary material as itpases over the rollers. It will be noted that an insulating sleeve 33(Fig. 4) is provided on each roller 27, the purpose of which will laterbe apparent. One wheel of each pulley frame 8 is provided with aninsulating bushing 34 for a purpose which will hereafter be apparent.Alternate wheels in the pulley frames are thus insulated. A battery 35of suitable strength isconnected to the tracks 6 and 7 by means of wires36 and 37. It will be apparent therefore that as shown in Fig.1 thesection of filamentary material held between the two pulley frames 8 andpassing over the coating rollers is subjected to the potential of thebattery 35 in the following manner: 8 From battery 35, through Wire 37,.track 7, a wheel of a pulley frame 8, agripper 16, the filamentarymaterial 23,through another gripper 16, a wheel of another pulley frame8, track'6, wire 36 and back to the opposite side of the battery 35. Theapplication of this voltage to the wire causes the passage of a desiredcurrent therethrough to heat it. The rollers 27 are spaced a su1t-'a'ble distance from each other so that after a portion of the coatinghas been applied by one roller the current will glow the wire betweenthat roller and the next one .so that the filamentary material isalternately coated and glowed a plurality of timesbefore the operationis complete. I 3

Adjacent the forward end of the conveyer belt 1, is another conveyer orbaking frame. This frame comprises a plurality of vertical standardport-ions 38, 39, 40 and 41. at the upper ends of which are pulleys 42and 43 and at the lower ends of which are pulleys 44 and 45. Over thesepulleys conveyer belts 46 and 47 are adapted to pass. These belts movealong the outer faces of the uprights 38 to 41, inclusive. Pulleys 42and 43 are mounted'on a shaft 46 and the pulleys 44 and 45 are mountedThe ends of these bars extend beyond the ends of the standard portionsand to the middle of the side faces of the pulleys 42 to 45, inclusive.These conducting bars provide an electrical contact surface for aplurality of material gripping devices mounted on the conveyer belts 46and 47. These gripper devices are somewhat similar in form to the onesprevious] mentioned with respect to the conveyer be t 1 and comprise agripper 52 (see Fig. 2) mounted on a bracket 53 which is suitablyfastened by screw means to the conveyer belts 46 and 47 The bracketport-ion 53 is providedwith portions 54 which are adapted to ext-endinwardly on each side of the standard portions to make contact with theconductive bars above mentioned. In addition each bracket is provided onone side with a contact clip 55 (see Fig. 2) which is adapted to makecontact with a plate 56 on the standards aswill be hereafter explained.Each of the grippers 52 is provided with a trailing portion 56 at itslower end.

As the filamentary material is being fed forward by the main conveyerbelt- 1, a point is reached where a section of this material has beenfed beyond the coating device and is in a position adjacent the lowerend of the above mentioned baking conveyer to be severed from the mainbody of the material and carried by the frame until the coating liquidon the material has been properly baked and dried. In order to effectthis result, at the instant the forward portion of the material is inthe position just described, one of the pulley frames 8 willbe inposition about to make contact with a cam surface 57 which cam surfacecontrols the actuation of an electrical switch 58. This switch controlsthe energization of wire 59 and wire 60. When this cam 57 is operatedthe following circuit is closed:

From battery 35, through Wire 61, wire 62, wire 59, switch 58, wire 60,wire 63, the

armature of a motor 64, wire 65, back to the other side of the battery35. A, field winding 66 of the motor 64 is connected on one side to thewire 65 and. on-the other side through wire 67 to wire 62 and from this.connection it is apparent that the field winding is always in directconnection with the battery 35. When the-switch 58 is closed thereforethe motor 64 is started and slowly moves the conveyer belts 46 and 47 inthe direction indicated by the arrows in Fig. 1 with respect to thesebelts. Therefore, the

gripping devices on these belts which are in position adjacent thecoated material are moved forward. In their forward movement the rearportions 56. of the grippers contact with cam surface 68 mounted on asuitable standard 69, the action of this. cam surface being to cause thegripper mechanism to open. The gripper mechanism, due

to theaction of the cam surface 68, remains open until its jaws surroundthe coated material. At this instant the rear edge 56 of the grippermoves off the front edge of the cam surface 68 and causes the grippermechanism to embrace the coated material. Immediately thereafter therear portions '56 of the gripper mechanism momentarily contact wlthspring switch members 70 which are fastened to the sup-port 69. 'Theswitch members 70 are connected by wires 71 and a wire 72 which leads tothe mid-pointof the battery 35. It is evident therefore that dur-.

ing the instant that the gripper mechanism is in contact with the switchmembers 7 0 and similar gripping mechanism on the main conveyer belt 2.The application of this comparatively large potential to such a smalllength'of material causes it to be fused off and thereby cause theseverance of the forward portion of the coated material from theremainder. The conveyer frame continues slowly to rotate and a point isreached shortly after the material is gripped by the grippers 52 whenthe rear spring contact 55 on the bracket 53 makes contact with a meofthe gripper. The circuit whereby this is" brought about is as follows iFrom battery 35, through wire 61, the conductor bar 48, through the sideportions 54 of a gripper member 52 through the contact sprin 55 of saidgripper member, through the plate 56, through wire 73, through wire 63,to one side of the armature of motor 64, thence to wire 65, and back tothe other side of'the battery. The upper end of the plate 56 provides adefinite sharp edge and is definitely positioned along the edge of theupright standard 38 so that the energization ofthe motor 64 is cut offexactly at the desired instant so that the movement of conveyer belts 46and 47 may be terminated exactly in the position desired. When themovement of'the belts is thus terminated, another gripper mechanism hasbeen brought around into position ready to engage the coated material.After a length of coated material has been carried around by theconveyer belts 46 and 47, the time comes when the rear portion 56 ofeach gripper contacts with cam surface 74 (see Fig. 2) at the end oftheir pathsof movement and this engagement causes the gripper members 52to be open to release the coated .ing moved upward by the bakingconveyer mechanism, the conveyer belt-1 and its associated mechanismsare still moving to ad- Vance the filamentary material over the coatingmechanism and beyond it adjacent the I baking conveyer to be latersevered and carried up by the same. ment of the baking conveyer beltsand the coating conveyer belts is such that a new section of coatedmaterial is brought adjacent the baking conveyer belt each time a set ofgripper devices on the baking conveyer belt is broughtinto grippingposition. It

The speed of movehas been calculated that the speed of movement of thebaking conveyer belts 46 and 47 for one complete revolution shouldconsume about two hours time which is thought to be sufiieient tosuitably dry the coated'material. The baking of the material carried bythe belts 46 and 47 is brought about by passing a current therethroughwhile they are being thus carried. The application of this current tothe material while on the baking frame is brought out by reason of thefact that the rippers which grip the material thereon aTso contactthrough side members 54 with the conducting bars 48 to 51, in-

clusiveI These bars are electrically connected respectively to Wires 61and 65 which wires are connected to opposite sides of the batterywhereby the potential of the battery 35 is applied to the ends of thecoated material.

. It is evident that this invention is not limited to the particulartype of filamentary material employed neither is it limited to anyparticular kind of coating therefor. The apparatus as described,however, is particularly adapted for applying to nickel wire, a coatingof a gelatinous glue-like substance composed of bariumcarbonate andstrontium carbonate in a solution of water.

This kind of coating as is well known in the vacuum tube art, possesseshigh thermionic activity when heated in a vacuum. As previously stated,the solution of the carbonates in container 28 should be heatedsufiiciently to give the desired consistency. The coating materialpreferably should be a thick paste so that the grooves of the rollers 27are practically filled with the material. This insures that the wire 23in passing over the rollers 27 is practically immersed in the coatingmaterial thereby insuring a substantial uniform coating. The coatingmaterial above described while at ordinary temperatures acting as aninsulating material, acts as a fairly good conductor when it is heated.

means for coating said piece of material, and

electrical means for severing portions of the coated piece of materialtherefrom by fusion.

2. In combination, means for feeding a .-continuous piece of filamentarymaterial,

means for coating said piece of material, and means for electricallyheating a small length of said material whereby said material is severedby fusion.

3. In combination, means for gripping .and feeding filamentary material,a second means for gripping said material at regular lntervals, andmeans for impressing a difference of electrical potential between saidgripping means to fuse the material there- I i i between. V I

4. The method which comprises feeding forward a continuous filamentarymateria coating said filamentary material. while being heated by anelectric current, and severing a portion of the-coated material byfusion as said material is fed foward.

5. The method which comprises feeding a continuous piece of material,coating said piece of material while being heated by an electriccurrent, severing a portion of the coated piece of material by fusionand baking the coated portion by the application of current thereto.

6. The method which comprises g'rippinga definite portion of acontinuous piece of material, coating said portion while being heated byan electric current, severing said coated portion therefrom by fusion,passing said severed portion to a baking frame, and subjecting theportion to current while on said frame.

7. The method which comprises feeding forward a continuous piece ofmaterial, alternately coating and glowing said piece of material andsevering portions of said piece of material by fusion as saidmaterial isfed forward.

8. A machine for feeding forward material comprisin means-for feeding acontinuous piece 0 material, and means operating after said material hasbeen fed forward for applying potential to a portion of the material tosever a length of material from the main body thereof by fusion as saidmaterial is fed forward.

9. A machine for feeding material which comprises means for gripping adefinite length of the material, means for feeding the material forward,means for coating said gripped length, means for applying a potential tosaid gripped length during coating, and means for applying a potentialto a portion of said gripped length after coatingto sever the lengthfrom the mam body of material.

10. A machine for feeding material which comprises means for gripping adefinite length of the material, means for feeding the material forward,means for coating the gripped length, means for applying a potential tothe length during coating. means cooperating with said gripping meansfor causing a portion of said length after coating to be severed, meansfor gripping said severed length simultaneous with the severing thereof,and means for applying a baking potential to said severed length afterfusing. i

' 11. A machine for feeding material which comprises an endlessconveyer, a plurality of spaced material grippers on sa1d conveyer,means cooperating with said grippers to cause portions of said materialto be severed and gripping means. acting simultaneous with the severingmeans to, convey the severed portions.

12. A machine for coating material comprising an endless conveyer, aplurality of spaced grippers on said conveyer, means to cause thegrippers periodically to seize the material, coating means in the pathof the grippers, /and means to apply a potential between the grippers.

13. A machine for coating material comprisin an endless conveyer, aplurality of space grippers on said conveyer, coating mechanism in thepath of said grippers, a second system of grippers adapted to move in adifferent direction from the first set of grippers, means for causingsaid second set of grippers to seize a portion of the coated material,and means acting simultaneously with the seizing and cooperating withsaid conveyer grippers to cause said portion to be severed from thematerial.

14. A machine for coating material com prising an endless conveyer, aplurality of material grippers on said conveyer, a coating mechanism inthe path of the grippers, a second set of grippers adapted to seizeportions of the coated material, Ineans acting simultaneously with theseizing and cooperating with said first set of grippers to cause theseized portion to be severed and means for applying a potential to thesevered portions to bake the same.

15. A material conveying mechanism comprising an endless belt, theplurality of material gripping devices on said belt, cam mechanismlocated in the path of the movement of said grippers to open them forthe seizure of a portion of the material, and electric circuit mechanismactuated by the grippers immediately after the seizure of a portion ofthe material whereby a potential is applied to the material adjacent toseized points to sever the same by fusing of the main body of thematerial.

16. -A machine for conveying and drying material which comprises anendless conveyer, a plurality of material gripping means on saidconveyer, a plurality of electrical conductors adjacent to saidgrippers, means on said grippers adapted continuously to contact withsaid conductors, and means for applying electrical potential to saidconductors, for heating the material to be fed by said conveyor.

17. The method Which comprises feeding a continuous conductivefilamentary material, coating said filamentary material, passingelectric current through said.ma-

terial during the coating operation, and pe spaced grippers on'riodically electrically heating a portion of said material to sever itby fusion.

18. p The method which comprises gripping a definite portion of acontinuous conductive material, coating said-material, passing electriccurrent therethrough during the coating operation, periodically severingthe coated portion, passing said'seve'red portion to a baking frame, andsubjecting the coated portion to current while on said frame.

19. The method'which comprises gripping a definite portion of acontinuous filamentary material, coating said portion while said portionis being heated, severing said coated portion, passing said severedportion to a. baking frame, and heating said portion while on saidframe.

20. A machine for coating material comprising an endless conveyor, aplurality of said conveyor, means to cause the grippers periodically toseize the material, coating means in the path of said grippers, andmeans for heating said material while being coated by said coatingmeans.

21. A machine for feeding material which I comprises an endlessconveyor, a plurality of spaced material grippers attached to saidconveyor, means cooperating with said grippers for causing the severingof said material into portions of equal length.

22. A machine for feeding material comprising spaced material gripperson said conveyor, means cooperating with said grippers for causing thesevering of portions of said material, and mechanism for gripping andfor conveying said severed portions away from the region of saidconveyor.

23. A machine for coating material comprising an" endless conveyor, aplurality of spaced grippers on said conveyor, coating mechanism in thepath of said grippers, a second set of grippers adapted to move in adifierent direction from' said first set of grippers, means for causingsaid second set of grippers to seize a portion of the coated PAUL somvRIN.

an endless conveyor, a plurality of-

